On Wed, 2014-01-29 at 18:28 +0000, Leif Lindholm wrote: > On Wed, Jan 22, 2014 at 11:20:55AM +0000, Will Deacon wrote: > > > +#ifdef CONFIG_CPU_CP15 > > > +/* Macro for setting/clearing bits in sctlr */ > > > + .macro update_sctlr, set:req, clear:req, tmp:req, tmp2:req > > > + mrc p15, 0, \tmp, c1, c0, 0 > > > + ldr \tmp2, =\set > > > + orr \tmp, \tmp, \tmp2 > > > + ldr \tmp2, =\clear > > > + mvn \tmp2, \tmp2 > > > + and \tmp, \tmp, \tmp2 > > > + mcr p15, 0, \tmp, c1, c0, 0 > > > > I think this would be cleaner if you force the caller to put set and clear > > into registers beforehand, rather than have to do the literal load every > > time. Also, I don't think set and clear should be required (and then you can > > lose tmp2 as well). > > I can't figure out how to make register-parameters non-required > (i.e. conditionalise on whether an optional parameter was provided), > so my attempt of refactoring actually ends up using an additional > register: > Register parameters are just strings, so how about this: .macro foo bar=, baz= .ifnc \bar, mov \bar,#0 .endif .ifnc \baz, mov \baz,#1 .endif .endm foo x0 foo foo x1, x2 foo ,x3 Results in: 0000000000000000 <.text>: 0: d2800000 mov x0, #0x0 // #0 4: d2800001 mov x1, #0x0 // #0 8: d2800022 mov x2, #0x1 // #1 c: d2800023 mov x3, #0x1 // #1 -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
